Laminated glass structure



Aprili 23, 1948.V J, L DAKE ET AL y 2,398,888

LAMINATED GLAS S STRUCTURE Filed Mayls, 1942' Gttorueg Patented Apr. 23, 1946 LAMINATED GLASS s'rnUo'rUnE John L. Drake and George B. Watkins, Toledo, Ohio, assignors to Libbey-Owens-Ford Glass 4Company, Toledo, Ohio, a corporation of Ohio Application May 15, 1942, serial No.' 443,090 4 claims. (cl. isi- 2.71)

'I'he present invention relates to improvements in laminated glass structures.

The type of laminated glass structureto which this invention more particularly relates comprises two sheets of glass and an interposed layer of thermoplastic adherent thereto to provide a composite structure and in which the surface area of the plastic interlayer is ygreater than the surface area of the glass sheets so that it extends beyond the edges-of said sheets to provide a flexible attaching and sealing iiange.

This laminated structure is adapted to be mounted in the opening to be glazed by clamping the extended portion only of the plastic in y for all practical purposes will not be transmitted directly to the glass, thereby reducing or eliminating the tendency of 'cracking or shattering thereof from such causes.. In other words, lthere is provided a flexible mounting to absorb torsional `strain and vibration and to reduce breakage resulting from the imposition of. mechanical strains on the glass during installation or in service.

Another advantage `of this type of laminated structure, particularlywhen used in airplanes, is that it can be mounted in a supporting frame with the outer face of said structure flush with the outer surface of said frame, whereby to reduce air resistance and permit more perfect streamlining.

One of the special uses of a laminated glass structure of this type is `for glazing stratosphere planes in which pressurized cabins, turrets or Y other compartments are provided to obviate the necessity for each occupant of the plane having an individual oxygen supply. Ordinarily, in this type of structure, the two sheets of glass have the same surface area and are so arranged that the edges thereof align with one another. Al-

though the extended plastic laminated glass structure above describedrcomes close to achieving the desired objectives of a .ush mounting and flexibility in the glass installation. it is not entirely satisfactory in all respects-since it relies solely upon the plastic interlayer for'stability and anchorage in the aircraft. For instance, the plastic interlayers now used tend to flow at relatively moderate temperatures, and this plastic vflowis governed by time, temperature,and pressure; The pressure is considerable in the extended plastic mounting, since the attaching flange bears the glass load and also must withstand pressure differentials between the inside and outside ofthe plane. Pressure tests conducted on dilierent types of mountings for aircraft laminated glass indicate that the extended plastic unit for airplane glazing, especially for pressurized cabins, is objectionable because of plastic flow and unsatisfactory solution of the problem of edge deiiection.

In an endeavor to overcome the above objections, it has been proposed to have one of the glass sheets relatively larger than the other to provide a so-called steppedv arrangement, the larger glass sheet being disposed inwardly of the plane and adapted to bear against a portion thereof' to take the thrust or pressure from the inside of the plane and thereby reduce edge deflection as well as to prevent the entire structure from being forced or blown outwardly by the internal presure built up in the' plane. However` in such structure, no provision is made for taking the thrust ory pressure from the outside of the plane andewhich may result in edge deflection and even at times be sufficient to force the struc- 4ture inwardly to lweaken or' shear the extended plastic.

It is an aim of this invention toV provide an improved extended plastic laminated glass structure which will take the thrust or pressure in both directions and thereby firmly retain the structure in place against forcible displacement as well as minimizing edge deflection in the extended plastic and the weakening or shearing thereof.

Another object of the invention is to provide such a laminated glass structure which will take the thrust or pressure in both" directions while. at the same time, maintaining 'the advantages of iiexibilityand iiush mounting.

A furtherobject of the invention is to provide such a laminated glass structure in which the two sheets of glass are associated with one another in suchI a manner that one sheet 'of glass takes -the pressure or thrust in one direction and the other sheet the pressure or thrust in the opposite direction.

Other objects and advantages of the invention will become more apparent during the course of glass I3 and I4 plane. The extended plastic 20 is then the following description, when taken in connection with the accompanying drawing.

In the drawing, wherein like numerals are employed to designate like parts throughout the Same I With reference nowto the drawing and particularly to Figs. 1 and 2, there is shown a laminated structure III mounted in II carried by the skin I2 nated structure a supporting frame of the plane. Thelami- I comprises the two sheets of and interposed layer of thermoplastic I adherent thereto. The glass sheets I3 and I4 may consist of ordinary plate or window glass and may be either fully tempered or semitempered or any desired .combination of glass sheetsmay be used. The plastic interlayer I5 is preferably formed of a synthetic resin material, such as, for example, a suitably plasticized polyvinyl acetal resin. However, different plastics' varying in thickness and physical characteristics may be employed and the invention is not limited to the use of any particular resin, class of resins, cellulosic derivatives or the like.

In accordance with the invention, the two sheets of glass I3 and I4 are of the same shape and size and are displaced diagonally or offset relative to one another as clearly shown in Fig. 1. I n other words, the glass sheet I 3 projects beyond the glass sheet I4 at the bottom thereof and also along one side as indicated at I6 and I'I respectively, while the glass sheet I4 projects beyond glass sheet I3 at the top thereof and also at the other side as indicated at I8 and I9 respectively. This results in a so-called semi-stepped arrangement, in thatveach glass sheet extendsbeyond the other glass sheet at two adjacent edges.

The glass'sheets I3 and I4 are also of lesser surface area than the plastic interlayer I5 so that theplastic interlayer extends beyond all of the edges of both glass sheets to provide a exible ,attaching and sealing flange 'which is `clamped in the supporting frame I I. Although not essential to the present invention, it is preferred that metal inserts 2I be embedded in the extended plastic. These metal inserts may consist of relatively thin strips of preferably flexible metal embedded in the extended plastic and projecting inwardly of the edges of the glass sheets.

In mounting the laminated structure I0, the glass sheet I3 is disposed outwardly and arranged iiush with the outer surface of the skin I2 of the clamped against the skin of the plane by the frame members 22 which are disposed outwardly of the edges of the inner glass sheet I4 and through which clamping bolts or the like 23 may be. passed.

said bolts also passing through the extended plastic attaching flange 20 and metal inserts 2 I. The frame members 22 may consist disposed at the four sides-of thestructure o'r they may be secured to or formed integral with one another to provide a continuous collar. Disposed between the plastic attaching flange 20 and skin Fig. 1 is a lfrontview of one form of laminated tions I6 and I1 of lap the frame members 22 at the bottom and one glass sheet 'shearing thereo forwardly directed ange 25 disposed opposite the peripheral edges of the cutter glass sheet I3.

Due to the diagonal displacement of the glass sheets I3 and I4, the projecting marginal porouter glass sheet I3 will overside of the structure, while the projecting margina] portions I8 and I9 of inner glass sheet I4 will overlap the s I2 of the plane as shown in Fig. 2. With such an arrangement, the marginal Portion I6 and I'I of glass sheet I3 will take the thrust or pressure from the outside of the plane and will bear against the respective frame members 22, while the marginal portions' I8 and I9 of I4l will take the thrust or pressure from the inside of the plane and bear against the skin I2 thereof.

As a result, accidental or forcible .displacement of the laminated structure I II from the supporting frame II from either the inside or outside of the frame will be effectively prevented. In addition, the projecting marginal portions of the glass sheets I3 and I4 which overlap the frame members 22 and skin I2 of the plane will improve the stability of the structure and the mounting thereof in the plane to minimize edge deflection of the extended plastic and the liability of tearing or These advantages are obtained While, at the same time, permitting a certain amount of floating movement of the structure within the supporting frame to thereby take advantage of the iiexibility of the plastic attaching flange 20. Thus, in mounting the structure, a relatively small space or gap a is left between the edges of the inner glass sheet I4 and frame members 22. As aresult, when the structure is subjected to outside pressure, it will be held against inward movement at the bottom and one side edge thereof'by the projecting marginal portion I Band I1 of outer glass sheet I3, while the top and opposite side of the structure will be permitted to move inwardly to obtain a. so-called rocking or pivotal action. On the other hand, when pressure is applied to the inside of the structure, it will be held lagainst outward movement at the top and one side edge theretof by the projecting marginal portions I8 and I 9 of inner glass sheet I4, while the bottom and opposite side of said structure will be' permitted to move outwardly. Consequently, there is provided a iiexible mounting for the structure permitting it to pivot or rock within the opening and thereby minimize strain in the laminated glass upon weaving or twisting of the plane` in ight.

In the embodiment of the invention illustrated Y in Figs. 3 and 4, the same advantages set forth .above are obtained by a slightly different arrangement of the glass sheets. As here shown.

the laminated structure is designated in its enthe twosheets of glass 29 and 30 and interposed of individual strips I2 of the plane is a. gasket 24 preferably of rubber, rubber composition or the like. 'I'he gasket that the outer sheet 29 thereof as indicated the exible attaching :Bange 3B layer'of thermoplastic 3| adherent thereto. 'I'he two .glass sheets 29 and 30 are lrectangular and associated with one another in such a manner extends a short-distance 30 at the top and bottom beyond inner sheet at 32-and 33,whi1e the inner sheet 30 projects a short distance beyond outer sheet 29 at the opposite sides as indicated at 34 and 35. The plastic interlayer 3| extends beyond the edges of both sheets of glass to provide within which is preferably xembedded the metal inserts Il.

21 carried by the outer wall or skin 28 ofA aseaese 3 The laminated structure 28 is mounted in the trame 21 in substantially the same manner` as in Fig. 2 by means of clamping bolts or the like 3d which pass through the frame members 3e, extended plastic 36, rubber gasket 40, and skin 28 of the plane. In this case, the projecting end portions 32 and 33 of the outerl glass sheet 2d overlap the frame vmembers 39 and thereby take the inward thrust or pressure, while the projecting end portions 34' and 35 of the inner glass sheet 30 overlap the skin 28 of the plane and take the outward thrust or pressure. This form of the invention also provides for a certain amount of ilexibility in the laminated structure to minimize the introduction of localized strains in the unit when the plane is in ight.

It is to be understood that the forms of the invention herewith shown and described are to be taken as illustrative embodiments only of the same', and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

We claim: l

1. A laminated `glass structure comprising two sheets of glass'and an interposed layer of thermopiastic adherent thereto. said glass sheets being so arranged relative to one another that one sheet' extends beyond the other sheet at one edge o! the structure while said second sheet extends beyond the iirst sheet at another edge of the structure. the plastic inter-layer extending beyond theedsesotbothsheetsotslaes.

2. A laminated glass structure comprising two sheets oi glass and an interposed layer ofv thermoplastic adherent thereto, said glass sheets being offset relative to one another in such a manner that one sheet extends beyond the other sheet at two edges of the structure while said second sheet extends beyond the rst sheet at the other two edges of the structure, the plastic interlayer extending beyond the edges of both sheets of glass.

3. A laminated glass structure comprising two sheets of glass and an interposed layer of thermoplastic adherent thereto, said 'glass sheets being displaced diagonally with respect to one ,another so that one sheet extends beyond the other sheet at two adjacent edges of the structure while said second sheet extendsbeyond the rst sheet at the other two adjacent edges of the structure, the plastic interlayer extending beyond the edges oi both sheets oi glass.

4. A laminated glass structure comprising two sheets of glass and an interposed layer of thermoplastic adherent thereto, said glass sheets being substantially rectangular and so arranged that one sheet extends beyond the other sheet at two opposite edges of the structure while said second sheet extends beyond the iirst sheet at the other two opposite edses of the structure, the E plastic interlayer extending beyond the edges of both sheets of Glass.

JOHN L. BRAKE.

GEORGE B. WATKINS. 

